With the rapid development of broadband services, network-to-network interconnection is used more and more to carry more services. According to the technology used, there may be a variety of ways within the network to protect links and nodes thereon. With increasingly strong demands for traffic protection and increasingly high requirements, operators proposed the demands for protection on the network interconnection. Herein the protection can be achieved by using port aggregation, and the commonly used method can be port aggregation or ring protection. In the existing IEEE (Institute of Electrical and Electronics Engineers) standard 802.1AX, the link aggregation currently supports the port aggregation on one node and therefore can only be used for link protection but cannot protect nodes at the network edge interface.
Therefore, in order to apply to the diversity of network-to-network interconnected area networking ways, and to achieve not only the protection for links but also the protection for edge nodes, the IEEE Standards Association proposed extended link aggregation, which achieves the link and node dual redundant network interconnected protection demands by means of a distribution link aggregation group DRNI, namely, an portal of the aggregation group consists of a plurality of nodes, and the aggregation links of the plurality of nodes form a link aggregation group (referred to as LAG). As shown in FIG. 1, two portals A and B in the link aggregation group consist of two and three systems, respectively: the portal A comprises system 1 and system 2, and the portal B comprises system 3, system 4, and system 5, a plurality of links of these five systems are aggregated together to form a distributed LAG. Through this distributed LAG, dual protection of links and nodes can be achieved.
The system 1 and the system 2 in the Portal A need to be connected through an intra-portal link, thus ensuring that the portal B sees that the portal A to which it is connected via a link aggregation group is a logical node; similarly, the system 3, the system 4 and the system 5 in the portal B also need to be connected through intra-portal links, thus ensuring that the portal A sees that the portal B to which it is connected via a link aggregation group is a logical node. After a plurality of links interconnected between the logical nodes in the portal A and the logic nodes in the portal B form a distributed link aggregation group through the LACP (Link Aggregation Control Protocol) control message interaction.
The DRNI interconnects two or more systems through a distributed relay (referred to as DR), wherein each system operates the link aggregation, thereby forming one Portal. For the peer system connected to the Portal, the peer system considers what it is connected to is an analog system. For this purpose, various systems within a Portal need to interact and negotiate through a distributed relay to unify parameters between these systems and notify to the LACP to interact with the other portal of the link aggregation group.
There are three kinds of interfaces on the DR, and they are Gateway Interface, Intra-portal Interface and Aggregate Interface, respectively. The DR functions to send messages (UP messages) received from the aggregation interface to the gateway or to discard them, and to send messages (DOWN messages) received from the gateway interface to the aggregator or to discard them. The DR decides whether to forward or discard a message according to the conversation to which the received message belongs, and configurations of the gateway algorithm and the port algorithm are also operated based on the conversation. Traffic of each conversation is assigned with one gateway link at most, and the traffic of each conversation also corresponds to one aggregation interface at most. When the DR in multiple systems within one portal do not have the consistent message distribution way, it will cause problems such as messages out of order, forming a ring or message loss, and therefore when there is the case that the distribution ways are inconsistent between multiple systems, it is also needed to interact via the distributed relay to unify the distribution ways in different systems or isolate the service traffic the distribution ways of which are not uniform.